Jody Dax

Markers of acute and chronic asphyxia in infants with meconium-stained amniotic fluid

OBJECTIVE Cord blood pH, lactate, hypoxanthine, and erythropoietin levels have all been used as markers of either acute or chronic asphyxia. We sought to determine whether these index values were significantly different in infants with or without meconium-stained amniotic fluid. STUDY DESIGN Fifty-six pregnant women in spontaneous labor at term were divided into two groups on the basis of the presence or absence of meconium-stained amniotic fluid. All meconium-stained fluid was centrifuged, and the volume percentage of particulate matter (i.e., meconium) was recorded. Umbilical artery blood and mixed arterial and venous cord blood were obtained at each delivery. Lactate, hypoxanthine, and erythropoietin levels were measured. Statistical analysis included Student t test and rank sum statistics where appropriate. Normal and Spearman correlation coefficients were also used. RESULTS There were no significant differences in mean umbilical artery pH (7.26 +/- 0.06 vs 7.25 +/- 0.10), lactate levels (32.8 +/- 10 mg/dl vs 30.4 +/- 14.2 mg/dl), and hypoxanthine levels (13.4 +/- 6.7 mumol/L vs 14.0 +/- 6.0 mumol/L) in newborns with meconium (n = 28) compared with controls (n = 28). Erythropoietin levels were significantly greater in newborns with meconium (median 39.5 mIU/ml vs 26.8 mIU/ml, p = 0.039). There was no correlation between the amount of particulate matter and any marker of asphyxia. CONCLUSIONS There was no correlation between markers of acute asphyxia (i.e., umbilical artery blood pH, lactate, or hypoxanthine) and meconium. However, erythropoietin levels were significantly elevated in newborns with meconium-stained amniotic fluid. This latter marker may better correlate with chronic asphyxia.

Prediction of the severity of meconium aspiration syndrome

OBJECTIVE Meconium aspiration syndrome is associated with increased neonatal morbidity and mortality. We sought to determine whether the need for neonatal mechanical ventilation or prolonged ventilation (> or = 3 days) was predictable from antepartum, intrapartum, and immediate neonatal events. STUDY DESIGN Between 1987 and 1989, 8003 of 43,906 (18%) live infants had meconium-stained amniotic fluid; 82 of these infants had clinical and radiographic evidence of meconium aspiration, and of these 82, 39 (48%) required mechanical ventilation. Predictors of ventilation or prolonged ventilation were determined by means of stepwise logistic regression. RESULTS Predictors of neonatal ventilation included fetal tachycardia, interval from meconium detection to delivery, low 5-minute Apgar score, respiratory distress necessitating intubation in the delivery suite, and delivery by cesarean section. Sensitivity was 72%, and specificity was 64%; the model was incorrect in 32% of the cases. Predictors of prolonged ventilation were ominous fetal heart rate tracing, umbilical arterial pH < 7.20, birth weight > 90th percentile, nulliparity, and Apgar score > 4 at 1 minute and < or = 6 at 5 minutes. Sensitivity was 67%, and specificity was 91%; prolonged ventilation was incorrectly predicted in 17% of the cases. CONCLUSIONS Use of these models to determine the need for mechanical ventilation or prolonged ventilatory assistance will enhance identification of infants at risk of severe meconium aspiration and will lead to early transfer to the neonatal intensive care unit for intense observation and management.

Fetal Effects of Prophylactic Ephedrine and Maternal Hypotension During Regional Anesthesia for Cesarean Section

The purpose of this study was to evaluate the effects of a prophylactic intravenous bolus of ephedrine on the incidence and severity of maternal hypotension and on neonatal outcome. Term healthy parturients (n = 122) scheduled for elective repeat cesarean section under regional anesthesia were studied. Ninety-two women received 10 mg ephedrine as a prophylactic intravenous bolus prior to intrathecal epidural local anesthesia. Thirty parturients who served as controls did not receive prophylactic ephedrine. Maternal blood pressures, Apgar scores, and umbilical cord blood acid-base status were evaluated. Sixty-three of 92 women (69%) who received intravenous prophylactic ephedrine prior to regional anesthesia developed hypotension compared to 21 (70%) controls. The mean (+/- SD) lowest systolic blood pressure was similar in both groups (95.6 +/- 12.9 vs. 96 +/- 8.9 mmHg; P = 0.86). The mean (+/-SD) fetal pH was significantly lower with prophylactic ephedrine than controls (7.24 +/- 0.07 vs. 7.28 +/- 0.05; P = 0.001). The frequency of umbilical artery blood pH < 7.20 was 10.6% for the ephedrine group vs. 3.2% for controls (P = 0.024). Among newborns of hypotensive mothers, the frequency of umbilical artery blood pH < 7.20 was 30.2% and 4.6% for the ephedrine and control groups, respectively (P = 0.018). Intravenous prophylaxis with ephedrine did not significantly decrease the frequency of hypotension in women receiving regional anesthesia and resulted in a greater proportion of umbilical artery blood pH values < 7.20.

Genital herpes during pregnancy: No lesions, no cesarean

Objectives To determine the effects at our hospital of adoption of the 1988 guidelines recommended by ACOG for management of genital herpes infections during pregnancy. Methods Between 1984–1986, 96 pregnancies complicated by active genital herpes were delivered at Parkland Hospital. The outcome of these pregnancies were compared with 217 similar pregnancies managed after implementation of the 1988 ACOG herpes guidelines. Results Adoption of the 1988 ACOG herpes guidelines resulted in a 37% decrease in the use of cesarean delivery for women with genital herpes infections at our hospital. Most of this decrease was because the new guidelines eliminated the need for a confirmatory negative herpes culture before permitting vaginal deliver. No neonatal herpes infections occourred as a result of impliemnting the ACOG recommindations. Conclusion The rate of cesarean delivery for women with genital herpes infections during pregnancy declined significantly at our hospital as a result of the adoption of ACOG herpes guidelines, and there were no neonatal consequences, such as increased incidence of neonatal herpes simplex virus infection.

Subcutaneous tissue: to suture or not to suture at cesarean section.

Objective: The null hypothesis for this investigation was that there was no difference in the frequency of wound disruption between women who had their subcutaneous tissues approximated with suture and those who did not during cesarean section. Methods: During alternating months, consecutive women delivered by cesarean section either did (N = 716) or did not (N = 693) have their subcutaneous tissues closed with suture. All data were analyzed using chi square, Students t-test, Fishers exact probability test, analysis of variance, or logistic regression. Results: A 32% decrease in the frequency of wound disruption was observed when subcutaneous tissues were brought into apposition with suture at cesarean section (P = 0.03). Conclusions: Closure of Scarpas and Campers fascia with suture during cesarean section significantly decreased the frequency of wound disruption in this population.

Chorioamnionitis: association of nonreassuring fetal heart-rate patterns and interval from diagnosis to delivery on neonatal outcome.

Objective: The purpose of this study was to determine whether selected fetal heart-rate (FHR) patterns and the interval from diagnosis to delivery in pregnancies complicated by chorioamnionitis could predict neonatal outcome. Methods: During a 6-month period, 217 consecutive patients with acute chorioamnionitis were prospectively identified in labor. Following delivery, the fetal monitor strips and hospital courses were reviewed for both the mother and neonate. Multiple logistic regression was used to analyze the presence of a nonreassuring FHR pattern and the effect on neonatal outcome. Fisher exact tests were used to analyze the time intervals from the diagnosis of chorioamnionitis to delivery and their significance on neonatal outcome parameters. Results: The overall incidence of chorioamnionitis in our population was 2.3%. None of the independent variables analyzed following the diagnosis of chorioamnionitis until delivery were significantly associated with an umbilical artery (Ua) pH < 7.20. There were no differences in cord pH, Apgar scores, sepsis, admission to special-care nursery, and oxygen requirements in neonates based on the duration of time from the diagnosis of chorioamnionitis to delivery in our study. None of the newborns had pathologic fetal acidemia (Ua pH < 7.00). None of the FHR patterns we identified after the diagnosis of acute chorioamnionitis were significantly associated with neonates with a Ua pH < 7.20. Conclusions: An interval from diagnosis to delivery of up to 12 h plays little if any role in neonatal outcome.

Ex vivo human placental transfer of human immunodeficiency virus-1 p24 antigen☆

OBJECTIVE Our purpose was to determine whether human immunodeficiency virus-1 p24 antigen crosses the human placenta and, if so, to determine its clearance index relative to antipyrine. STUDY DESIGN Eight term human placentas from uncomplicated vaginal or cesarean section deliveries were studied by ex vivo placental perfusion to determine the incidence and concentration required to obtain passage of p24 antigen into the fetal circulation. The concentration of p24 antigen was determined by antigen-capture enzyme immunoassay. RESULTS The passage of p24 antigen into the fetal circulation was observed in three of five placentas studied when the p24 antigen concentration in the maternal circulation was 2942.8 +/- 401 pg/ml. When the p24 concentration in the maternal circulation was raised approximately fourfold to 14506 +/- 4124 pg/ml, p24 antigen passed to the fetal circulation in two of three placentas and in three of three placentas in the closed perfusion system. CONCLUSIONS p24 antigen crossed the human placenta to the fetal circulation in what appears to be a concentration-dependent manner.

Subcuticular Suture Versus Staples for Skin Closure in Vertical Skin Incisions in Cesarean Sections

The purpose of the present study was to evaluate the frequency of wound complications comparing staples to suture closure of the skin. During a 6-month period, all patients who underwent cesarean delivery were assigned to have their skin approximated with either subcuticular sutures or surgical staples. The remainder of the closure techniques were the same in each group. Risk factors for wound complications were identified and statistically analyzed. Twelve hundred and eighty-nine patients were evaluated. Of the 731 women with skin closure via staples, 66 (9%) had a superficial wound separation compared with only 13 (2.3%) of 558 when subcuticular suture was used to approximate the skin edges (P < 0.0001). This was significant only for vertical skin incisions. Thus, closure of the skin with subcuticular suture at the time of cesarean reduced the incidence of wound disruption by more than fourfold.